I'm not exactly sure which servers do it, but on some of the retake servers the map chooser doesn't change the map at the end, which leaves players needing to !rtv to get it to change. !nextmap and !rtv work fine however, which leads me to believe that the proper convars aren't set. Make sure the following is set somewheres either in server.cfg or retakes.cfg
mp_match_end_changelevel 1
mp_match_end_restart 0
mp_match_end_changelevel 1
mp_match_end_restart 0